Safety device for pitmen.



J. P. THIESSEN & E. BECKER. SAFETY DEVICE FOR PITMEN.

APPLICATION FILED JULY 27, 1908.

In I II jz forzzl a JOHANNES FERDINANDETHIESSEN AND EMIL BECKER, OF NEUMIlNSTER, GERMANY.

SAFETY DEVICE FOR PITMEN.

Specification of Letters Patent.

Patented Feb. 9, 1909.

Application filed July 27, 1908. Serial No. 445,543.

To all whom it may concern:

Be it known that we, J OHANNES FERDINAND THESSEN, of 21 Miihlenhof, Neumiinster i. H., Germany, engineer, and EMIL BECKER, of 32 Grossflecken, Neumiinster i. H., Ger- I many, engineer, both subjects of the King of Prussia, have invented certain new and useful Improvementsm Safety Devices for Pitmen.

intentionally points of weakness in parts of machinery with the object of insuring that the said parts shall break at these points in case of overload.

Now the present invention has for its object to provide an improved construction of such intentional points of weakness, and itconsists in forming the part to be intentionally weakened, of two pieces connected together by a point allowing of relative rotary movement between the said two pieces, in providing a further connection between the said two pieces of such strength and nature that so 10 as there is no overload relative rotary motion between the two pieces will be prevented by the said further connection, and the. said two ieces will operate as one rigid part. On tile occurrence of overload however, the said further connection will give way and allow of relative rotary movement between the two pieces whereby the part composed of the said two pieces will become shorter or longer as the case may be,

'and relieve the strain produced upon said part of the overload. The drawing illustrates by way of example the application of this invention to an eccentric (designed for a crusher or breaker) shown in side elevation partly in section.

a, is the shaft on which the eccentric sheave b, is mounted.

0, is the eccentric stra connected by means of a pm, 03, with t e-eccentric rod part, e.

f, is the pin in the rod, 6, for connection ,to the part (not shown) to be operated.

The rod part, e, issubstantially of U- shape in cross section and its two sides embrace the lower half of the strap, 0. This lower half'is formed with a transverse bearng flan e g, upon which fits a similar bearlng sur ace, h, formed on the rod part, c.

It has already been proposed to provide The two flanges g, and it, are held against each other by a nutted bolt, '4'. The strength of this bolt is made such that it will withstand the strain of normal load. If however through overload, the strain exceeds the normal strain, the bolt, i, will break,

and then the rod part 6 will rotate relatively to the eccentric strap until the points 0:, cl and f are in one and thesame straight; line, the flanges g and it moving apart from each other.

Asthe sum of the distances from a to d and from (Z to f is greater than the distance from a to f, when the parts are in their working ositions, the eccentric will become so much onger by the breaking of the bolt 2' that all excessive strain will cease.

In the same manner this invention may be applied to an eccentric rod actin as a part in com ression, with the'di erence that in case .0 breakage of the safety device, the eccentric will become shorter instead of longer.

Having thus described our invention. what we claim is new and desire to secure by Letters Patent is 1. In a machine, the combination of two pivotally connected members, said members having also outer pivot points means of predetermined strength for holding said members bem so constructed that on the breakage of said holding means the distance bebers against pivotal movement, said memtween the outer pivot points of said members will be varied to relieve the strain on the machine.

2. In a machine, the combination of two members connected to; rotate relatively to each other, said members having outer pivot points breakable means of predetermined 2 e I V e12,04e

rotation under normal conditions, said set our hands in presence of two subscribmovable member bemg constructed to move mg wltnesses.

on, the breakage of said holding means to 4 JOHANNES FERDINAND THIESSEN. vary' the distance between the outer pivot EMIL BECKER.

5 points of said members to relieve the strain Witnesses: v

on the macifine J UmUs RQPKE,

In testimony whereof we have hereunto BRUNO Goson. 

